Apparatus for driving a tool through a predetermined stroke



July 2, 1957 M. BALSAM I 2,797,584

APPARATUS FOR DRIVING A TOOL THROUGH A PREDETERMINED STROKE Filid May 4,1953 4 Sheets-Sheet l 5s I /J A I I INVENTOR. 4 Maumcs I"). BHLSAM July2, 1957 M. M. BALSAM 2,797,584

APPARATUS FOR DRIVINGv A TQOL THROUGH A PREDETERMINED STROKE Filed My 4,1953 v 4 Sheets-Sheet 2 INVENTOR. MAURICE M. I BAL SAP? wiw , July 2,1957 M. M. BALSAM 2,797,534

' APPARATUS FOR DRIVING A TOOL THROUGH A PREDETERMINED STROKE Filed May4, 1983. v 4'Sheets-She et a INVENTOR. Mnumcz m.

United States Patent APPARATUS FOR DRIVING A T061. THROUGH APREDETERMINED STROKE Maurice M. Balsam, New York, N. Y.

Application May 4, 1953, Serial No. 352,886

Claims. (CI. 74-42) suddenly and at a very fast and powerful rate sothat with conventional machines it is essential that proper guides beprovided for the tools. Moreover, due to the fast and powerful movementby the conventional machines of this type, injuries both to theapparatus and operators are a fairly frequent occurrence. Such injuriesalso result from the fact that these known machines re peatedly drivethe tools through their driving stroke as long as an actuating member isengaged, so that if the operator does not, for example, immediatelyrelease a foot pedal or the like which actuates the machine, the tool isdriven more than once.

One of the objects of the present invention is to overcome drawbacks ofthe above mentioned type by providing a tool driving apparatus whichrequires only a relatively small amount of energy. a

A further object of the present invention is to provide a tool drivingapparatus which drives the tool at a relatively slow rate so thatelaborate structures to take up shock and the like are not required.

Another object of the present invention is to provide a means to enablea tool to yieldably engage an object to be worked on before being drivenagainst the latter.

An additional object of the present invention is totprovide a means forguaranteeing that a drive means will become automatically disengagedfrom a tool after the latter is driven through one stroke, even thoughthe actuating member for the drive means is still engaged.

Still another object of the present invention is to provide an apparatuscapable of accomplishing all of the above objects while at the same timebeing made up of a relatively small number of simple and ruggedlyconstructed parts.

With the above objects in view, the present invention mainly consists ofan apparatus for driving a tool through a predetermined stroke, thisapparatus including a support means which supports a tool carrying meansfor movement through a predetermined stroke. A drive means is mounted onthe support means for driving the tool carrying means through thepredetermined stroke, and a transe mission means, for releasablyinterconnecting the tool carrying means with the drive means to transmita drive from the drive means to the tool carrying means to drive thelatter through its predetermined stroke, is connected to the toolcarrying means for movement between a rest position out of engagementwith the drive means and an operating position in engagement with thedrive means. A moving means is mounted on the support means and ilocated adjacent to the transmission means for moving the latter fromits rest to its operating position, and a disengaging means is locatedon the support means for automatically disengaging the transmissionmeans from the drive means after the tool carrying means has been driventhrough its predetermined stroke.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings, inwhich:

Fig. 1 is a partly sectional, side elevational view of an apparatusconstructed in accordance with the present in: vention;

Fig. 2 is a fragmentary view of a part of the structure of Fig. 1 shownin a different position thereof;

Fig. 3 is a fragmentary view of a part of the structure of Fig. 1 shownin still another position thereof;

Fig. 4 is a view taken along the line 44 of Fig. 1 in the direction ofthe arrows;

Fig. 5 is a fragmentary, partly sectional view of a detail of theapparatus of the invention taken along the line 5-5 of Fig. 4 in thedirection of the arrows;

Figs. 6 and 7 are respectively side and front views of a transmissionmeans constructed in accordance with the present invention;

Figs. 8 and 9 are respectively side and front views of a moving memberconstructed in accordance with the present invention; and

Fig. 10 is a fragmentary view of the drive apparatus of the presentinvention.

Referring now to the drawings, and in particular to Fig. 1 thereof, itwill be seen that the apparatus of the invention includes a supportmeans 15 in the form of a frame 16 having a pair of spaced top sections17 (Figs. 1 and'4) which carry a pivot pin 18. A tool carrying means inthe form of an elongated member 19 having suitable openings formedtherein is turnably carried at one end thereof by the pin 18, and a tool20 is pivotally suspended from the tool carrying means 19 to make animpression or the like on a work piece located on the portion 21 of thesupporting frame 16, for example.

A transmission means 22 is connected to the tool carrying means 19 formovement between a rest and an operating position, this transmissionmeans being best shown in Figs. 6 and 7 and comprising at its endportion adjacent to the tool carrying member 19, a pair of opposite sideparts 23 each of which is formed with an elongated slot 24, these slotsof the opposite side parts 23 being aligned with each other.

.30 is fixed to the member 28 adjacent to the bottom thereof, and aspring 31 is located about the bottom end portion of the screw member 28and abuts against the collar 30, this spring 31 also being located abouta stem 32 fixed to a U-shaped member 33 which is urged toward the pivotpin 34 by the spring 31, this pivot pin 34 extending through one of theopenings of the tool carrying member 19 and the slots 24 so that thespring means form-ed by members 2833 urge the pivot pin 34 to one end ofthe slots 24.

. As is apparent from Fig. 5, the side parts 23 are pro videdwit-h guidemembers 35 which guide the U-shaped member ,33 for movement along thespace between the side parts 23, and this U-shaped member 33 engages thetop of the tool carrying means 19 to urge the latter downwardly and thetransmission means 22 upwardly until the pin 34 engages, the bottom endsof the slots 24.

The block 25 is formed with a threaded bore into which a threaded stud36 extends, this stud 36 having a pair of lock nuts 37 thereon, the stud36 also extending into a threaded opening of a block 38 located betweenand fixed to a second pair of side parts 39 of the transmission means22. The block 38 is fixed to side parts 39 in the same way that block 25is fixed to side parts 23, and a member 49 having a free hooked endportion 41 is fixed to the side parts 39 at the end thereof oppositefrom block 38, as is shown in Figs, 6 and 7. A pin 42 is fixed to theside parts 39 and extends therebetween as shown in Fig. 7.

As is most clearly shown in Figs. 4 and 10, the drive for the apparatusof the invention is derived from an electric motor 43 of relativelysmall size which has its shaft fixed to a worm 44 engaging a worm wheel45 which is in turn fixed to a drive shaft 46 mounted for rotation onthe supporting frame 16, as is most clearly shown in Fig. 4. A disc 47is fixed to the drive shaft 46 for rotation therewith, and it will beseen from Fig.4 that this drive shaft is supported not only by theopposite sides of supporting frame 16, but also by an intermediate wall48. A pair of pins 49 is fixed to the disc 47 for rotation therewith andextends toward the wall 48. As is most clearly shown in Figs. 1-3, thepins 49 are located on opposite sides of the drive shaft 46 and at thesame radial distance therefrom so that when the disc 47 turns in thedirection of the arrow 50, the pins 49 rotate through a predeterminedcircular path.

As is shown in Fig. l, the supporting frame 16 carries a spring-pressedstop pin 51 which limits movement of the transmission means 22 in acounter-clockwise direction about its pivotal connection to the toolcarrying means .19. A spring 52 is fixed to the support means and thetransmission means 22 to urge the latter to the rest position shown inFig. 1.

As is shown in Fig. l, a guide block 53 is located between the sidewalls of the supporting frame 16, and a moving member 54 engages theinclined surface of this guide block for reciprocating movementtherealong. As is apparent from Figs. 8 and 9 which show the details ofthis moving member, the latter includes a pair of opposite side .parts55 connected at one end to the hooked member 56 and at their oppositeend to a pivot pin 57 which, as is shown'in Fig. 1, extends through anopening of a foot pedal 58 pivotally mounted on the supporting frame 16at 59 and being urged to the rest position there of, shown in Fig. 1,against the block 53 by the spring 60, a stop bar 61 being fixed to thesupporting frame 66 beneath the foot pedal 58 to limit the downwardmovement thereof against the action of the spring 60.

The above described apparatus operates as follows:

In the position of Fig. 1, the apparatus is at rest and the operatorplaces a work piece to be engaged by the tool 20, for example, beneaththe latter. Then, the operator depresses the foot pedal 58 so that itrotates about the pivot 59 until it engages the stop 61. As is evidentfrom Fig. 1, this depression of the foot pedal 58 will cause the movingmember 54 to move downwardly along the block 53 so that the hooked endportion 56 of moving member 54 engages pin 42 of the transmission means22 and turns the latter on the tool carrying means 19 in a clockwisedirection, as viewed in Fig. 1, against the action of spring 52.

As may be seen from Fig. 2, this movement of the transmission means 22upon depression of the foot pedal 58 causes the free hooked end 41 oftransmission means 22 to engage the drive shaft 46 and to become locatedwithin the circular path through which the pins 49 rotate. The first ofthese pins to engage the hooked end 41, that is, the top pin shown inFig. 2, will move the transmis' sion means downwardly to turn the toolcarrying means 19 through its stroke in a clockwise direction aboutpivot 18, as viewed in Fig. 1.

Thus, the transmission means 22 is moved downwardly against the actionof spring 52 until the pin 49 engaging the hooked end portion 41 movesslightly beyond the lowermost part of its stroke, as is shown in Fig. 3.At this point, the hooked end portion 40 is engaged by the drive shaft46 to be prevented by the latter from moving with the pin 49, so thatthis drive shaft 46 acts as an automatic disengaging means fordisengaging the transmission means 22 from either of the pins 49 whenthe tool carrying means 19 has been turned through its predeterminedstroke. When the hooked end 41 is disengaged from the drive means, thetransmission means 22 is moved under the influence of the spring means52 against the stop 51 and back to its rest position in Fig. 1 where itis located out of the path through which. pins 49 move.

As is evident from Fig. l, the pin 42 moves downwardly away from thehooked end 56 of moving mcmher 54 when the hooked end 41 of transmissionmeans 22 is engaged :by a drive pin 49, so that the drive meansautomatically disengages the transmission means 22 from the moving meanswhich moves it into its operating position, and it is impossible for thetransmission 22 to again become located in its operating position untilthe foot pedal 58 is again actuated.

It is evident that during engagement of a drive pin 49 with thetransmission means 22, the latter moves in a substantially downwarddirection to turn the tool carrying member 19 until the tool 20 engagesa work piece. At this point, the spring 31 is compressed while the tool20 remains in engagement with the work piece, and this affords theoperator an opportunity to very accurately set the tool 20 on the workpiece during the period that the spring 31 is being compressed. When thetops of the slots 24 engage the pin 34, the movement of the tool iscontinued, so that the apparatus of the invention provides a period oftime during which the tool engages the workpiece and may be adjustedthereon before the tool continues to move in its driving stroke.

As was mentioned above, the motor 43 is of a fairly small size and thegear reduction obtained through worm 44 and worm wheel 45 is such thatdisc 47 rotates at a very slow rate. Thus, the period during which thetool 20 resiliently bears against the workpiece is fairly substantial.

It will be seen from Fig. 4 that the free hooked end 41 of thetransmission means is located between the wall 48 and the disc 47, andthat the pins 49 extend toward wall 48 while the left wall of supportingframe l6 shown in Fig. 4 is located close to the disc 47. Thisarrangement provides supports for the shaft 46 which is located veryclose to the disc 47 so that the apparatus of the invention can veryeasily withstand-tremendous forces applied to the tool 20 with therelatively small motor 43.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types oftool driving apparatus diflfering from the type described above.

While the invention has been illustrated and described as embodied inapparatus for driving a tool for a predetermined stroke, it is notintended to be limited to the details shown, since various modificationsand structural changes may be made without departing in any way from thespirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand,therefore,suchadaptations should and are intended to be comprehendedwithin the meaning and range of equivalence of the forming claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. Apparatus for driving a tool through a predetermined stroke,comprising, in combination, support means; tool carrying means mountedon said support means for movement through a predetermined stroke; drivemeans mounted on said support means for driving said tool carrying meansthrough said predetermined stroke; transmission means for releasablyinterconnecting said tool carrying means with said drive means totransmit a drive from said drive means to said tool carrying means todrive the latter through said predetermined stroke; connecting meansinterconnecting said transmission means with said tool carrying meansfor movement between a rest position out of engagement with said drivemeans and an operating position in engagement with said drive means,said connecting means including a resilient member which becomescompressed when a tool carried by said tool carrying means encounters aresistance; moving means mounted on said support means and being locatedadjacent said transmission means for moving the latter from said rest tosaid operating position thereof; and disengaging means located on saidsupport means for automatically disengaging said transmission means fromsaid drive means after said tool carrying means has been driven throughsaid predetermined stroke.

2. Apparatus as defined in claim 1 and wherein said transmission meansincludes an elongated member having a hooked end, said drive meansincludes a rotating disc having a pin which engages said hooked end ofsaid elongated member of said transmission means when said transmissionmeans is in said operating position thereof, and wherein saiddisengaging means is formed by a shaft which carries said disc and whichdisengages said hooked end of said member from said pin when said dischas turned through a predetermined angle.

3. Apparatus for driving a tool through a predetermined stroke,comprising, in combination, a supporting frame; an elongated toolcarrying member mounted on said supporting frame for movement through apredetermined stroke; elongated transmission means having opposite endportions one of which is pivotally connected to said tool carryingmember so that said elongated transmission means is turnable between arest position and an operating position, and said elongated transmissionmeans having a free hooked end portion distant from said tool carryingmember; a drive shaft turnably mounted on said supporting frame forrotation about its axis and being located adjacent said free hooked endportion of said elongated transmission means; a disc fixed to said driveshaft for rotation therewith and being located in a plane parallel tothat in which said transmission means turns during movement between saidrest and operating positions thereof; a pin fixed to said disc,extending in a direction parallel to said drive shaft, and beingturnable through a predetermined circular path spaced from said hookedend portion of said transmission means when the latter is in said restposition, and intersecting said hooked end portion of said transmissionmeans when the latter is in said operating position thereof so that saidpin engages said hooked end portion of said transmission means and movesthe latter to drive said tool carrying member through said strokethereof when said transmission means is in said operating positionthereof and said drive shaft turns about its axis, said drive shaftengaging said transmission means at said hooked end portion thereof todisengage the latter from said pin after movement of said transmissionmeans and said tool carrying member therewith through a predetermineddistance corersponding to said stroke of said tool carrying member;spring means connected to said transmission means and said supportingframe for urging said transmission means to said rest position thereof;and moving means mounted on said supporting frame for moving saidtransmission means from said rest to said operating position thereof.

4. Apparatus for driving a tool through a predetermined stroke,comprising, in combination, a supporting frame; an elongated toolcarrying member mounted on said supporting frame for movement through apredetermined stroke; elongated transmission means having opposite endportions one of which is pivotally connected to said tool carryingmember so that said elongated transmission means is turnable between arest position and an operating position, and said elongated transmissionmeans having a free hooked end portion distant from said tool carryingmember; a drive shaft turn'ably mounted on said supporting frame forrotation about its axis and being located adjacent said free hooked endportion of said elongated transmission means; a disc fixed to said driveshaft for rotation therewith and being located in a plane parallel tothat in which said transmission means turns during movement between saidrest and operating positions thereof; a pin fixed to said disc,extending in a direction parallel to said drive shaft, and beingturnable through a predetermined circular path spaced from said hookedend portion of said transmission means when the latter is in said restposition, and intersecting said hooked end portion of said transmissionmeans when the latter is in said operating position thereof so that saidpin engages said hooked end portion of said transmission means and movesthe latter to drive said tool carrying member through said strokethereof when said transmission means is in said operating positionthereof and said drive shaft turns about its axis, said drive shaftengaging said transmission means at said hooked end portion thereof todisengage the latter from said pin after movement of said transmissionmeans and said tool carrying member therewith through a predetermineddistance corresponding to said stroke of said tool carrying member;spring means connected to said transmission means and said supportingframe for urging said transmission means to said rest position thereof;and moving means mounted on said supporting frame for moving saidtransmission means from said rest to said operating position thereof,said moving means comprising an elongated member mounted on saidsupporting frame for reciprocating'movement along a path different fromthat through which said transmission means moves when engaged by saidpin and said elongated member of said moving means also having a freehooked end portion, and said moving means comprising a second pin fixedto said transmission means and located in the path of movement of saidhooked end portion of said elongated moving member to be engaged by thelatter for moving said transmission means against the action of saidspring means from said rest to said operating position thereof, saidsecond pin moving away from said elongated member of said moving meansupon engagement of said transmission means with said pin fixed to saiddisc.

5. Apparatus for driving a tool through a predetermined stroke,comprising, in combination, a supporting frame; an elongated toolcarrying member mounted on said supporting frame for movement through apredetermined stroke; elongated transmission means having opposite endportions one of which is pivotally connected to said tool carryingmember so that said elongated transmission means is turnable between arest position and an operating position, and said elongated transmissionmeans haping a free hooked end portion distant from said tool carryingmember; a drive shaft turnably mounted on said supporting frame forrotation about its axis and being located adjacent said free hooked endportion of said elongated transmission means; a disc fixed to said driveshaft for rotation therewith and being located in a plane parallel tothat in which said transmission means turns during movement between saidrest and operating positions thereof; a pin fixed to said disc,extending in a direction parallel to said drive shaft, and beingturnable through a predetermined circular path spaced from saidhookedlend portion of said transmission means when the latter is in saidrest position, and intersecting'said hooked end portion of'saidtransmission means when the latter is in said operating position thereofso that said pin engages Said hooked end portion of said transmissionmeans and moves the latter to drive said tool carrying member throughsaid stroke thereof whensaid transmission means is in said operatingposition thereof and said drive shaft turns about its axis, said driveshaft engaging said transmission means at said hooked end portionthereof to disengage the latter from said pin after movement of saidtransmission means and said tool carrying member therewith through apredetermined distance corresponding to said stroke of said toolcarrying member; spring means connected to said transmission means andsaid supporting frame for urging said transmission means to said restposition thereof; and moving means mounted on said supporting frame formoving said transmission means from said rest to said operating positionthereof, said moving means comprising an elongated member mounted onsaid supporting frame for reciprocating movement along a path differentfrom that through which said transmission means moves when engaged bysaid pin and said elongated member of said moving means also having afree hooked end portion, and said moving means comprising a second pinfixed to said transmission means and located in the path of movement ofsaid hooked end portion of said elongated moving member to be engaged bythe latter for moving said transmission means against the action of saidspring means from said rest to said operating position thereof, saidsecond pin moving away from said elongated member of said moving meansupon engagement of said transmission means with said pin fixed to saiddisc, and said moving means including a second spring means connected tosaid frame for urging said hooked end of said moving member to an idleposition out of engagement with said second pin.

6. Apparatus for driving a tool through a predetermined stroke,comprising, in combination, a supporting frame; an elongated toolcarrying member mounted on said supporting frame for movement through apredetermined stroke; elongated transmission means having opposite endportions one of which is pivotally connected to said tool carryingmember so that said elongated transmission means is turnable between arest position and an operating position, and said elongated transmissionmeans having a free hooked endportion distant from said tool carryingmember; a drive shaft tumably mounted on said supporting frame forrotation about its axis and being located adjacent said free hooked endportion of said elongated transmission means; a disc fixed to said driveshaft for rotation therewith and being located in a plane parallel tothat in which said transmission means turns during movement between saidrest and operating positions thereof; a pin fixed to said disc,extending in a direction parallel to said drive shaft. and beingturnable through a predetermined circular path spaced from said hookedend portion of said transmission means when the latter is in said restposition, and intersecting said hooked end portion of said transmissionmeans when the latter is in said operating position thereof so that saidpin engages said hooked end portion of said transmission means and movesthe latter to drive said tool carrying member through said strokethereof when said transmission means is in said operating positionthereof and said drive shaft turns about its axis, said drive shaftengaging said transmission means at said hooked end portion thereof todisengage the latter from said pin after movement of said transmissionmeans and said tool carrying member therewith through a predetermineddistance corresponding to said stroke of said tool carrying member;spring means connected to said transmission means and said supportingframe for urging said transmission means to said rest position thereof;and moving means mounted on said supporting frame for moving saidtransmission means from said rest to said operating position thereof,

said moving means comprising an elongated member mounted on saidsupporting frame for reciprocating movement alonga path different fromthat through which said transmission means moves when engaged by saidpin and said elongated member of said moving means also having a freehooked end portion, and said moving means comprising a second pin fixedto said transmission means and located in the path of movement of saidhooked end portion of said elongated moving member to be,

engaged by the iatter for moving said transmission means against theaction of said spring means from said rest to said operating positionthereof, said second pin moving away from said elongated member of saidmoving means upon engagement of said transmissionmeans, with said pinfixed to said disc, and said moving means, including a second springmeans connected to said frame,

for urging said hooked end of said moving member to an idle position outof engagement with said second pin, said moving means also including afoot pedal pivotally mounted on said supporting frame and beingconnected to said elongated moving member for moving the latter againstthe action of said second spring means into engagement with said secondpin to move said transmission means against the action of said firstspring means from said rest to said operating position thereof.

7. Apparatus for driving a tool through a predetermined stroke,comprising, in combination, a supporting frame; an elongated toolcarrying member mounted on said supporting frame for movement through apredetermined stroke; elongated transmission means having opposite endportions one of which is pivotally connected to said tool carryingmember so that said elongated transmission means is turnable between arest position and an operating position, and said elongated transmissionmeans having a free hooked end portion distant from said tool carryingmember, said one end portion of said transmission means being formedwith a slot passing therethrough and said transmission means beingconnected to said tool carrying member through the medium of a pivotpassing through said tool carrying member and said slot; a drive shaftturnably mounted on said supporting frame for rotation about its axisand being located adjacent said free hooked end portion of saidelongated transmission means; a disc fixed to said drive shaft forrotation therewith and being located in a plane parallel to that inwhich said transmission means turns during movement between said restand operating positions thereof; a pin fixed to said disc, extending ina direction parallel to said drive shaft, and being turnable through apredetermined circular path spaced from said hooked end portion of saidtransmission means when the latter is in said rest position, andintersecting said hooked end portion of said transmission means when thelatter is in said operating position thereof so that said pin engagessaid hooked end portion of said transmission means and moves the latterto drive said tool carrying member through said stroke thereof when saidtransmission means is in said operating position thereof and said driveshaft turns about its axis, said drive shaft engaging said transmissionmeans at said hooked end portion thereof to disengage the latter fromsaid pin after movement of said transmission means and said toolcarrying member therewith through a predetermined distance correspondingto said stroke of said tool carrying member; spring means connected tosaid transmission means and said supporting frame for urging saidtransmission means to said rest position thereof; moving means mountedon said supporting frame for moving said transmission means from saidrest to said operating position thereof; and second spring means mountedon said one end portion of said transmission means and engaging saidtool carrying member to urge said pivot to one end of said slot so thatwhen a tool carried by said tool carrying member encounters aresistance,

said second spring means will be compressed till said pivot engages theopposite end of said slot before said transmission means moves said toolcarrying member through said predetermined stroke.

8. In an apparatus for driving a tool through a predetermined stroke, incombination, support means; a drive shaft mounted for rotation about itsaxis on said support means; a plate fixed to said shaft for rotationtherewith; a pin fixed to said plate for rotation therewith so as toturn through a predetermined circle located about said axis; and atransmission member having a hooked end and being mounted on saidsupport means for movement at said hooked end thereof into and out ofthe path of movement of said pin and for movement into engagement withsaid shaft, so that when said hooked end of said transmission member islocated in said path, said pin will engage said transmission member tomove the latter toward said shaft during turning of said plate aboutsaid axis, said shaft engaging said transmission member to automaticallydisengage the same from said pin.

9. In an apparatus for driving a tool through a pre determined stroke,in combination, support means; a drive shaft mounted for rotation aboutits axis on said support means; a disc fixed to said shaft for rotationtherewith, said shaft extending from at least one face of said disc; apair of pins fixed to said disc for rotation therewith, being spacedabout said axis, and extending from said face of said disc and at thesame radial distance from said axis so as to turn through apredetermined circle located about said axis; a transmission memberhaving a hooked end land being mounted on said support means formovement at said hooked end thereof into and out of the path of movementof said pins and for movement into engagement with said shaft, so thatwhen said hooked end of said transmission member is located in saidpath, one of said pins will engage said transmission member to move thelatter during turning of said disc about said axis, said shaft engagingsaid transmission member to automatically disengage the same from saidpin; and moving means operable at the will of the operator for movingsaid transmission member into and out of said path of movement of saidpins.

10. In an apparatus for driving a tool through a predetermined stroke,in combination, support means; a drive shaft mounted for rotation aboutits axis on said support means; a plate fixed to said shaft for rotationtherewith; a pin fixed to said plate for rotation therewith so as toturn through a predetermined circle located about said axis; latransmission member having a hooked end and being mounted on saidsupport means for movement at said hooked end thereof into and out ofthe path of movement of said pin and for movement into engagement withsaid shaft, so that when said hooked end of said transmission member islocated in said plath, said pin will engage said transmission member tomove the latter toward said shaft during turning of said plate aboutsaid axis, said shaft engaging said transmisson member to automaticallydisengage the same from said pin; and moving means operable at the willof the operator for moving said transmission member into land out ofsaid path of movement of said pin.

References Cited in the file of this patent UNITED STATES PATENTS610,129 Ericson Aug. 30, 1898 1,114,044 Roberts Oct. 20, 1914 1,337,533Trumble Apr. 20, 1920 2,382,174 Rott Aug. 14, 1945

